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Artykuły w czasopismach na temat "Composés volatils"
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Filipiak, Wojciech, Matthias Wenzel, Clemens Ager, Chris A. Mayhew, Tomasz Bogiel, Robert Włodarski i Markus Nagl. "Molecular Analysis of Volatile Metabolites Synthesized by Candida albicans and Staphylococcus aureus in In Vitro Cultures and Bronchoalveolar Lavage Specimens Reflecting Single- or Duo-Factor Pneumonia". Biomolecules 14, nr 7 (2.07.2024): 788. http://dx.doi.org/10.3390/biom14070788.
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Current microbiological methods for pneumonia diagnosis require invasive specimen collection and time-consuming analytical procedures. There is a need for less invasive and faster methods to detect lower respiratory tract infections. The analysis of volatile metabolites excreted by pathogenic microorganisms provides the basis for developing such a method. Given the synergistic role of Candida albicans in increasing the virulence of pathogenic bacteria causing pneumonia and the cross-kingdom metabolic interactions between microorganisms, we compare the emission of volatiles from Candida albicans yeasts and the bacteria Staphylococcus aureus using single and mixed co-cultures and apply that knowledge to human in vivo investigations. Gas chromatography–mass spectrometry (GC-MS) analysis resulted in the identification of sixty-eight volatiles that were found to have significantly different levels in cultures compared to reference medium samples. Certain volatiles were found in co-cultures that mainly originated from C. albicans metabolism (e.g., isobutyl acetate), whereas other volatiles primarily came from S. aureus (e.g., ethyl 2-methylbutyrate). Isopentyl valerate reflects synergic interactions of both microbes, as its level in co-cultures was found to be approximately three times higher than the sum of its amounts in monocultures. Hydrophilic–lipophilic-balanced (HLB) coated meshes for thin-film microextraction (TFME) were used to preconcentrate volatiles directly from bronchoalveolar lavage (BAL) specimens collected from patients suffering from ventilation-associated pneumonia (VAP), which was caused explicitly by C. albicans and S. aureus. GC-MS analyses confirmed the existence of in vitro-elucidated microbial VOCs in human specimens. Significant differences in BAL-extracted amounts respective to the pathogen-causing pneumonia were found. The model in vitro experiments provided evidence that cross-kingdom interactions between pathogenic microorganisms affect the synthesis of volatile compounds. The TFME meshes coated with HLB particles proved to be suitable for extracting VOCs from human material, enabling the translation of in vitro experiments on the microbial volatilome to the in vivo situation involving infected patients. This indicates the direction that should be taken for further clinical studies on VAP diagnosis based on volatile analysis.
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Magaña, Lizeth O., Parvathy Prem, Ariel N. Deutsch, Anna C. Martin, Heather M. Meyer, Caleb I. Fassett, Michael K. Barker i in. "Surface Roughness at the Moon’s South Pole: The Influence of Condensed Volatiles on Surface Roughness at the Moon’s South Pole". Planetary Science Journal 5, nr 2 (1.02.2024): 30. http://dx.doi.org/10.3847/psj/ad18da.
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Abstract Condensed volatiles within lunar permanently shadowed regions are of high scientific and resource utilization importance. Volatiles remain elusive and difficult to observe directly, due to low direct solar illumination. In this work, we investigate correlations between, as well as possible effects of, condensed volatiles and surface roughness. We analyze topographic roughness at 50 m and 30–120 m baselines of the lunar south pole (poleward of 85° S). We focus on six south polar craters of interest and their directly surrounding non-cold-trap areas: Faustini, Shoemaker, Haworth, Cabeus, Nobile, and an unnamed region. We further analyze six analogous equatorial craters to investigate the non-ice smoothing contributions: Morozov F, Rosenberger C, Van Maanen, Fraunhofer E, Brisbane, and Asclepi. Lastly, we compare a sunlit and a permanently shaded portion of the Amundsen crater floor. Utilizing data from the Lunar Reconnaissance Orbiter’s Lunar Orbiter Laser Altimeter (LOLA), Lyman Alpha Mapping Project (LAMP), Lunar Reconnaissance Orbiter Camera, and Diviner Lunar Radiometer Experiment, we find subdued roughness within cold traps but determine that roughness is not a unique identifier of condensed volatiles. However, a correlation between LOLA roughness, LAMP normalized Off-band/On-band albedo, temperature, and water-ice stability suggests possible terrain softening due to condensed volatiles, although we cannot rule out dust ponding and/or fairy castle structure contributions. We conclude that LAMP volatile signatures at the topmost ∼100 nm may be indicative of volatile deposits at depths beyond the LAMP sensing capabilities.
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Revadi, Santosh V., Vito Antonio Giannuzzi, Ramesh R. Vetukuri, William B. Walker i Paul G. Becher. "Larval response to frass and guaiacol: detection of an attractant produced by bacteria from Spodoptera littoralis frass". Journal of Pest Science 94, nr 4 (5.03.2021): 1105–18. http://dx.doi.org/10.1007/s10340-021-01352-9.
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AbstractLarval frass in herbivorous lepidopterans is mainly composed of plant-derived material and microbes from the gut. Despite the fact that frass from conspecific larvae repels female moths in Spodoptera littoralis from oviposition, the role of frass volatiles on larval foraging behavior is largely unknown. Here, we show that larvae of S. littoralis walk upwind to larval frass volatiles in a wind tunnel assay. We identified the frass volatile guaiacol (2-methoxyphenol) as key ligand for the S. littoralis odorant receptor (OR) SlitOr59 which we expressed heterologously. We isolated guaiacol-producing bacteria identified as Serratia marcescens from frass of larvae that were fed on cotton, and Enterobacter cloacae, E. ludwigii and Klebsiella sp. from frass derived from cabbage-fed larvae. In addition to guaiacol, we also identified volatiles acetoin, 3-methyl-1-butanol and dimethyl disulfide, in large proportions in headspace collections from the bacteria. A Y-tube olfactometer assay showed that fourth instar S. littoralis larvae are attracted to guaiacol. Moreover, cotton leaves treated with the insecticide Spinosad and guaiacol were highly attractive to the larvae. Our results provide a basis for management of the pest by directly targeting larvae, based on an attract-and-kill strategy. Further studies are needed to test the application of guaiacol for semiochemical-based pest management of Spodoptera pest species.
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Osei-Owusu, Jonathan, William K. Heve, Owusu Fordjour Aidoo, Maxwell Jnr Opoku, Joseph Apau, Kodwo Ninsin Dadzie, Bright Yaw Vigbedor i in. "Repellency Potential, Chemical Constituents of Ocimum Plant Essential Oils, and Their Headspace Volatiles against Anopheles gambiae s. s., Malaria Vector". Journal of Chemistry 2023 (14.07.2023): 1–12. http://dx.doi.org/10.1155/2023/3848998.
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African malaria mosquitoes (Anopheles gambiae sensu stricto) transmit a malaria parasite (Plasmodium falciparum) to humans. The current control strategies for the vector have mainly focussed on synthetic products, which negatively impact the environment and human health. Given the potential use of environmentally friendly plant-derived volatiles as a control, this work aims to examine and compare the repellency potential of essential oils and headspace volatiles from Ocimum gratissimum, Ocimum tenuiflorum, and Ocimum basilicum and their chemical compositions. The repellency potential and chemical composition of the plants were achieved by using the protected arm-in-cage method and gas chromatography-mass spectrometry (GC-MS) analysis. Among the three Ocimum species, both the essential oils and the headspace volatiles from O. tenuiflorum achieved the longest repellency time lengths of 90–120 minutes. One hundred and one (101) chemical constituents were identified in the headspace volatiles of the three Ocimum spp. Nonetheless, (−)-camphor, (E)-γ-bisabolene, terpinolene, β-chamigrene, cubedol, (E)-farnesol, germacrene D-4-ol, viridiflorol, γ-eudesmol, tetracyclo [6.3.2.0 (2,5).0(1,8)] tridecan-9-ol, 4,4-dimethyl, α-eudesmol, isolongifolol, and endo-borneol were unique only to O. tenuiflorum headspace volatiles. Either essential oils or headspace volatiles from O. tenuiflorum could offer longer protection time length to humans against An. gambiae. Though field studies are needed to assess the complementarity between the chemical constituents in the headspace volatiles of O. tenuiflorum, our observations provide a foundation for developing effective repellents against An. gambiae.
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Mülner, Pascal, Alessandro Bergna, Philipp Wagner, Dženana Sarajlić, Barbara Gstöttenmayr, Kristin Dietel, Rita Grosch, Tomislav Cernava i Gabriele Berg. "Microbiota Associated with Sclerotia of Soilborne Fungal Pathogens – A Novel Source of Biocontrol Agents Producing Bioactive Volatiles". Phytobiomes Journal 3, nr 2 (styczeń 2019): 125–36. http://dx.doi.org/10.1094/pbiomes-11-18-0051-r.
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Soilborne plant pathogens are an increasing problem in modern agriculture, and their ability to survive long periods in soil as persistent sclerotia makes control and treatment particularly challenging. To develop new control strategies, we explored bacteria associated with sclerotia of Sclerotinia sclerotiorum and Rhizoctonia solani, two soilborne fungi causing high yield losses. We combined different methodological approaches to get insights into the indigenous microbiota of sclerotia, to compare it to bacterial communities of the surrounding environment, and to identify novel biocontrol agents and antifungal volatiles. Analysis of 16S rRNA gene fragment amplicons revealed significant compositional differences in the bacterial microbiomes of Rhizoctonia sclerotia, the unaffected tuber surface and surrounding soil. Moreover, distinctive bacterial lineages were associated with specific sample types. Flavobacteriaceae and Caulobacteraceae were primarily found in unaffected areas, while Phyllobacteriaceae and Bradyrhizobiaceae were associated with sclerotia of R. solani. In parallel, we studied a strain collection isolated from sclerotia of the pathogens for emission of bioactive volatile compounds. Isolates of Bacillus, Pseudomonas, and Buttiauxella exhibited high antagonistic activity toward both soilborne pathogens and were shown to produce novel, not yet described volatiles. Differential imaging showed that volatiles emitted by the antagonists altered the melanized sclerotia surface of S. sclerotiorum. Interestingly, combinations of bacterial antagonists increased inhibition of mycelial growth up to 60% when compared with single isolates. Our study showed that fungal survival structures are associated with a specific microbiome, which is also a reservoir for new biocontrol agents.
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Marčetić, Mirjana, Dragana Božić, Marina Milenković, Branislava Lakušić i Nada Kovačević. "Chemical Composition and Antimicrobial Activity of Essential Oil of Different Parts of Seseli rigidum". Natural Product Communications 7, nr 8 (sierpień 2012): 1934578X1200700. http://dx.doi.org/10.1177/1934578x1200700832.
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The chemical composition and antimicrobial activity of the essential oil of the Balkan endemic species Seseli rigidum Waldst. & Kit. (Apiaceae) was investigated. The monoterpene α-pinene was predominant in the volatile oil from aerial parts (57.4%) and fruit (23.3%). In the essential oil of the aerial parts limonene (6.7%), camphene (5.8%) and sabinene (5.5%) were also present in high amounts, and in the fruit oil, β-phellandrene (17.4%) and sabinene (12.9%). On the contrary, the root essential oil was composed almost entirely of the polyacetylene falcarinol (88.8%). The antimicrobial activity of the root essential oil was significant against Staphylococcus aureus, S. epidermidis, Micrococcus luteus and Enterococcus faecalis (MICs 6.25–25.00 μg/mL). Volatile constituents from the root strongly inhibited the growth of methicillin-resistant strains of S. aureus (MICs 6.25–50.00 μg/mL). Anti-staphylococcal activity can be attributed to the main volatile constituent of S. rigidum root, falcarinol.
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Lyons, Sarah M., Sydney C. Morgan, Stephanie McCann, Samantha Sanderson, Brianne L. Newman, Tommaso Liccioli Watson, Vladimir Jiranek, Daniel M. Durall i Wesley F. Zandberg. "Unique volatile chemical profiles produced by indigenous and commercial strains of Saccharomyces uvarum and Saccharomyces cerevisiae during laboratory-scale Chardonnay fermentations". OENO One 55, nr 3 (27.07.2021): 101–22. http://dx.doi.org/10.20870/oeno-one.2021.55.3.4551.
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Each wine growing region hosts unique communities of indigenous yeast species, which may enter fermentation and contribute to the final flavour profile of wines. One of these species, Saccharomyces uvarum, is typically described as a cryotolerant yeast that produces relatively high levels of glycerol and rose-scented volatile compounds as compared with Saccharomyces cerevisiae, the main yeast in winemaking. Comparisons of fermentative and chemical properties between S. uvarum and S. cerevisiae at the species level are relatively common; however, a paucity of information has been collected on the potential variability present among S. uvarum strains. The objective of this study was to compare the fermentation kinetics and production of volatile compounds between indigenous and commercial Saccharomyces strains at different temperatures. We compared laboratory-scale fermentation of Chardonnay juice at 15 °C and 25 °C for 11 Saccharomyces yeast strains (six indigenous S. uvarum, one commercial S. uvarum, one indigenous S. cerevisiae and three commercial S. cerevisiae). Fermentation kinetics and the production of volatile compounds known to affect the organoleptic properties of wine were determined. The indigenous S. uvarum strains showed comparable kinetics to commercially sourced strains at both temperatures. Volatile compound production among the strains was more variable at 15 °C and resulted in unique chemical profiles at 15 °C as compared with 25 °C. Indigenous S. uvarum strains produced relatively high levels of 2-phenylethyl acetate and 2-phenylethanol, whereas these compounds were found at much lower levels in fermentations conducted by commercial strains of both S. cerevisiae and S. uvarum. Production of glycerol by indigenous S. uvarum strains did not differ from commercial strains in this study. Our findings demonstrate that indigenous strains of S. uvarum show functional variation among themselves. However, when compared with commercial S. cerevisiae and S. uvarum strains, they have comparable fermentation kinetics but unique volatile compound profiles, especially at low fermentation temperatures.
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Imade, Rose O., i Buniyamin A. Ayinde. "GC-MS analysis and invitro cytotoxic activity of Ocimum basilicum (Lamiaceae) volatile oil and active fraction composed majorly of estragole". Journal of Pharmacy & Bioresources 19, nr 3 (22.12.2022): 143–52. http://dx.doi.org/10.4314/jpb.v19i3.3.
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Ocimum basilicum leaves contain some bioactive compounds and this study was designed to evaluate the cytotoxic efficacy of its volatile oil and fractions. Preliminary screening of the oil obtained by hydrodistillation was carried out using bench-top assay methods employing tadpoles of Raniceps ranninus (10-40 μg/mL), nauplii of Artemia salina (10-1000 μg/mL) and radicles of Sorghum bicolor seeds (1-30 mg/mL). Application of column chromatography and preparative TLC on the oil resulted in fractions that were tested alongside the oil on breast (AU 565) and cervical (HeLa) cancer cell lines at 50 μg/mL. GCMS analysis was carried out on the oil and the most active fraction. A concentration dependent activity was observed in the preliminary screening with the bench-top assays. The active fraction produced greater growth inhibition of the radicle of S. bicolor seeds than the oil. Inhibitions of -1.02 and +23.02 % were realized against AU 565 and HeLa cell lines respectively with the oil, and these were increased to +33.19 and +89.3 % inhibitions respectively with the active fraction. GCMS results revealed the presence of estragole (88.61 %) as being most abundant in the fraction. This result shows the cytotoxic potential of O. basilicum volatile oil, which was increased in its estragole-containing fraction.
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BONNARME, PASCAL, CARMEN LAPADATESCU, MIREILLE YVON i HENRY-ERIC SPINNLER. "L-methionine degradation potentialities of cheese-ripening microorganisms". Journal of Dairy Research 68, nr 4 (listopad 2001): 663–74. http://dx.doi.org/10.1017/s002202990100509x.
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Volatile sulphur compounds are major flavouring compounds in many traditional fermented foods including cheeses. These compounds are products of the catabolism of L-methionine by cheese-ripening microorganisms. The diversity of L-methionine degradation by such microorganisms, however, remains to be characterized. The objective of this work was to compare the capacities to produce volatile sulphur compounds by five yeasts, Geotrichum candidum, Yarrowia lipolytica, Kluyveromyces lactis, Debaryomyces hansenii, Saccharomyces cerevisiae and five bacteria, Brevibacterium linens, Corynebacterium glutamicum, Arthrobacter sp., Micrococcus luteus and Staphylococcus equorum of technological interest for cheese-ripening. The ability of whole cells of these microorganisms to generate volatile sulphur compounds from L-methionine was compared. The microorganisms produced a wide spectrum of sulphur compounds including methanethiol, dimethylsulfide, dimethyldisulfide, dimethyltrisulfide and also S-methylthioesters, which varied in amount and type according to strain. Most of the yeasts produced methanethiol, dimethylsulfide, dimethyldisulfide and dimethyltrisulfide but did not produce S-methylthioesters, apart from G. candidum that produced S-methyl thioacetate. Bacteria, especially Arth. sp. and Brevi. linens, produced the highest amounts and the greatest variety of volatile sulphur compounds including methanethiol, sulfides and S-methylthioesters, e.g. S-methyl thioacetate, S-methyl thiobutyrate, S-methyl thiopropionate and S-methyl thioisovalerate. Cell-free extracts of all the yeasts and bacteria were examined for the activity of enzymes possibly involved in L-methionine catabolism, i.e. L-methionine demethiolase, L-methionine aminotransferase and L-methionine deaminase. They all possessed L-methionine demethiolase activity, while some (K. lactis, Deb. hansenii, Arth. sp., Staph. equorum) were deficient in L-methionine aminotransferase, and none produced L-methionine deaminase. The catabolism of L-methionine in these microorganisms is discussed.
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Silva, Adriana Lins, Rita De Cássia Costa Araújo, Marcos Rodrigues, Áurea Izabel Aguiar Fonseca e. Souza i Wilton Pires da Cruz. "Composting and vermicomposting residues of açaí and babassu for sustainable agriculture in Amazon". Cultura Agronômica: Revista de Ciências Agronômicas 29, nr 2 (13.07.2020): 217–31. http://dx.doi.org/10.32929/2446-8355.2020v29n2p217-231.
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Agroindustrial wastes in southeastern Amazon are abundant and there are policies encouraging proper disposal for such wastes for sustainable agriculture. In this study we compared the chemical parameters of composts resulting from composting and vermicomposting sheep manure added to agroindustrial wastes as a bulking agent. Piles of compost were created using sheep manure, fruit waste, and a bulking agent. The treatments consisted of compost piles of: Tc - sheep manure and fruit pulp; Ta - sheep manure, fruit pulp and triturated açaí seeds; Ts - sheep manure, fruit pulp and sawdust, and Tb - sheep manure, fruit pulp and babassu coconut residue. After 50 days, a fraction of the compost from each pile was transferred to vermireactors to compare processes. At the end of the experiment, samples were taken in triplicate from all treatments in both composting and vermicomposting units for chemical analysis. The assessed variables were daily temperature of compost piles and vermireators, C/N ratio, Volatile solids (VS), total kjeldahl nitrogen (TKN), total phosphorus (TP), total potassium (TK), calcium (Ca), magnesium (Mg), sulfur (S), iron (Fe), copper (Cu), zinc (Zn), manganese (Mn), boron (Bo). Sawdust-based and babassu-based compost, from composting process, has the lower time for stabilization (about 40 days), pH closer to neutral and more efficient in reducing the C:N ratio than vermicomposts. Vermicomposting process increased the concentration of almost all nutrients in treatments, except for babassu-based compost.
Rozprawy doktorskie na temat "Composés volatils"
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Lesne, Priscille. "Etude expérimentale de la solubilité des volatils C-H-O-S dans les basaltes alcalins italiens : simulations numériques du dégazage chimique : application à l'Etna". Phd thesis, Université d'Orléans, 2008. http://tel.archives-ouvertes.fr/tel-00347906.
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Le volcanisme d'arc est connu pour ses fortes teneurs en volatiles, qui lui confèrent un degré de dangerosité élevé. L'étude des volatils majeurs C, H, O, S, présents dans les systèmes magmatiques apporte des informations importantes à la compréhension du fonctionnement des systèmes volcaniques, du point de vue chimique et physique. Ces informations sont primordiales pour la prévention du risque volcanique. Dans ce travail, nous avons déterminé de façon expérimentale les lois de solubilité des volatils majeurs, H2O, CO2 et S (SO2, H2S) présents dans les systèmes volcaniques pour trois basaltes alcalins de trois volcans italiens. L'utilisation d'un autoclave à chauffage interne, équipé d'un système de trempe rapide nous a permis de réaliser des expériences d'équilibre entre un liquide silicaté et une phase fluide en excès à haute température, et à des pressions allant jusqu'à 3000 bars. L'utilisation de méthodes courantes (FTIR, KFT, EMPA) pour l'analyse des volatils dissous dans ces verres basaltiques synthétisés, nous a permis d'obtenir des résultats à partir desquels les lois de solubilité de chacune des espèces volatiles ont été définies pour les verres basaltiques alcalins issus du Vésuve, de l'Etna et du Stromboli. L'étude expérimentale a permis de montrer l'importance des alcalins sur la solubilité de H2O à des pressions supérieures à 1000 bars, mais surtout sur la solubilité du CO2. L'introduction des lois de solubilité des volatils majeurs dans un modèle numérique, appliqué à l'Etna, permet de mieux comprendre les phénomènes de dégazage, en se référant aux données naturelles disponibles (inclusions vitreuses et chimie des gaz en sortie de conduit).
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Villeneuve, Marie-Pier. "Profils en acides gras, abondance de composés volatils et propriétés sensorielles du lait de vaches recevant de la fléole des prés sous forme de foin, d'ensilage ou de pâturage". Thesis, Université Laval, 2013. http://www.theses.ulaval.ca/2013/29997/29997.pdf.
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Afin d’évaluer l’effet du type de fourrage utilisé dans la ration sur la flaveur ainsi que sur le profil en acides gras et en composés volatils du lait, des vaches laitières ont reçu une ration à base de fléole des prés sous forme de foin, d’ensilage ou de pâturage. Le rapport acide palmitique sur acide oléique fût inférieur pour le lait issu du traitement pâturage comparativement aux autres traitements. Le type de fourrages a également affecté les teneurs en acides gras, alcools, aldéhydes, cétones, lactones et terpènes du lait. Des panélistes ont été en mesures de différencier les laits des traitements foin et pâturage. Les résultats de cette expérience montrent que les profils en acides gras et en composés volatils des sécrétions lactées peuvent être modulés par le type de fourrage servi aux vaches et que ces changements influencent les propriétés sensorielles du lait.
Książki na temat "Composés volatils"
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Singer, Julie. Lyrical Humor(s) in the “Fumeur” Songs. Redaktorzy Blake Howe, Stephanie Jensen-Moulton, Neil Lerner i Joseph Straus. Oxford University Press, 2016. http://dx.doi.org/10.1093/oxfordhb/9780199331444.013.26.
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A small corpus of late fourteenth-century comical lyrics, most composed by the poet Eustache Deschamps, presents the lyricist or performer as afumeur(literally, “smoker”): a creative but volatile artist with a melancholic nature. These texts and their musical settings engage in sophisticated play on late medieval medical understandings of madness and its cures. A new reading of these lyrics in light of Deschamps’s theorization of “natural” and “artificial” music reveals that a particularlydisabledembodiment underpins that author’s poetic vision; and the existence of a corpus of closely relatedfumeursongs composed by multiple authors invites us to revisit received ideas about disabled identity in the Middle Ages.
Części książek na temat "Composés volatils"
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Crespo, Julia, Margarita García, Teresa Arroyo, Valeria Romero i Juan M. Cabellos. "Effect of aging on lees on the volatile profile of Malvasia aromatica wines fermented with Saccharomyces native yeasts in PDO “Vinos de Madrid”". W New Advances in Saccharomyces [Working Title]. IntechOpen, 2023. http://dx.doi.org/10.5772/intechopen.1003667.
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The loss of aromatic and sensory quality in wines because of climate change in traditional winemaking areas is a challenge for winemakers. Aging on lees of the wine fermented with Saccharomyces native yeasts has been tested as a technique to try to improve the sensory characteristics of Malvasia aromatica white wines in PDO “Vinos de Madrid.” The grapes were pre-cold macerated and fermented with S. cerevisiae CLI 271 and CLI 889 (native yeast strains). Then, commercial lees were used for aging of wines for a five-month at low temperature in order to compare with the effect of S. cerevisiae CLI 271 and CLI 889 without lees treatment. Aromatic and organoleptic properties of wines aged on lees were studied using GC-FID and HS-SPME/GC–MS to quantify volatile compounds and a taster panel to sensorial analysis. There was a significant decrease in the ester family in wines aged on lees being more pronounced in CLI 889 wines. The treatment contributed to enhance the fruity and floral aromatic properties in CLI 271 and CLI 889 wines, respectively according to tasting panel, which showed a hedonic preference for CLI 271 wines without lees treatment and CLI 889 wines aged on lees.
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Wang, Rui, Chen-Hao Luo, Wen-jie Xia, Wen-yan He, Biao Liu, Ming-Liang Huang, Zeng-qian Hou i Di-cheng Zhu. "Role of Alkaline Magmatism in Formation of Porphyry Deposits in Nonarc Settings: Gangdese and Sanjiang Metallogenic Belts". W Tectonomagmatic Influences on Metallogeny and Hydrothermal Ore Deposits: A Tribute to Jeremy P. Richards (Volume II), 205–29. Society of Economic Geologists, 2021. http://dx.doi.org/10.5382/sp.24.12.
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Abstract The recent discovery of large Cenozoic porphyry copper deposits in the Tibetan Plateau has revealed atypical features. Their formation all postdate the India-Asia collision at 55 ± 10 Ma, and therefore they are not affiliated with normal arc magmatism. Three major nonarc porphyry copper belts or provinces in Tibet comprise the Gangdese porphyry Cu-Mo belt (>45 Mt Cu, 1.79 Mt Mo), the Yulong porphyry Cu-Mo belt (8.75 Mt Cu,1.04 Mt Mo), and the western Yunnan porphyry Cu-Mo-Au polymetallic province (~1 Mt Cu, ~1 Mt Mo, and 310 t Au). Alkaline volcanic rocks (lamprophyres, shoshonites, and potassic-ultrapotassic volcanic rocks) are common in these metallogenic belts and provinces, but the temporal, spatial, and genetic relationship between this magmatism and deposit formation remains enigmatic. There are two episodes of porphyry mineralization in the Tibetan Plateau, 45 to 35 and 22 to 11 Ma, and alkaline volcanic rocks are both contemporaneous with and spatially close to porphyry mineralization. Evolved Nd-Hf isotope compositions, and high Mg#, Cr, and Ni contents of Tibetan alkaline volcanic rocks suggest that they are derived from phlogopite-bearing lithospheric mantle, whereas the adakitic property and hybrid geochemical and isotopic features of the high Sr/Y granitoids suggest they are derived from partial melting of lower crust by mantle-derived alkaline mafic melt, with subsequent mixing. The mantle-derived alkaline magmas: (1) triggered water-flux melting of the thickened lower crust and generation of fertile high Sr/Y magmas with high water contents; (2) that dominate the source of ore-related magmas are more Au rich; (3) have variable oxidation states and some can oxidize residual sulfide in the lower crust to release Cu and Au for porphyry deposit formation; other lower crustal melts became oxidized via amphibole and/or garnet fractionation; and (4) provide higher S and Cl contents that are essential volatiles for deposit formation. We conclude that mantle-derived alkaline melts are vital to form porphyry deposits in nonarc settings, thus explaining the close spatial and temporal association of alkaline volcanic rocks and porphyry deposits in Cenozoic Tibet.
Streszczenia konferencji na temat "Composés volatils"
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Rees, A. C., J. F. Davidson, J. S. Dennis i A. N. Hayhurst. "The Rise and Combustion of Particles of Sewage Sludge and Petroleum Coke in a Slugging Fluidized Bed". W 18th International Conference on Fluidized Bed Combustion. ASMEDC, 2005. http://dx.doi.org/10.1115/fbc2005-78071.
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The rise-times, from just above the base to the top of the bed, of single particles of dried sewage sludge and of two types of petroleum coke were measured in a slugging bed of sand fluidized by air. The sewage sludge and the petroleum cokes contained, on an as received basis, 49.5, 9.0 and 0.5 wt.% volatile matter, respectively. The bed (i.d. 25.5 mm; height 1300 mm) was electrically heated to a fixed temperature between 700 and 900°C. Two sizes of sand were fluidized: +212, −300 μm and +710, −850 μm. The expansion of the bed was held constant by keeping the excess gas velocity at (U − Umf) = 190 mm/s. In a bed of the coarser sand, it was found that the time of rise of single particles of sewage sludge (< 4 mm diam.) was large enough to allow devolatilization and char burn-out to be complete before the particle reached the upper surface of the bed. The measured times of rise are significantly longer than those found in bubbling beds [12, 13]. Thus, a slugging bed, of say 2 m in depth, would have significantly better heat retention and contact of the volatile material with the particulate phase than a bubbling bed of the same depth. With the finer sand, particles of sewage sludge and of petroleum coke containing volatile material rose rapidly to the top of the bed, well before combustion was complete. Published theory [6] was used to predict the rise-times of inert particles in a hot slugging bed. The predictions compare favourably with measurements using petroleum coke containing negligible amounts of volatile material and moisture. The use of a modified form of Stokes’s law to predict the velocity of rise of inert particles is shown to compare well with experiments. The experimental results suggest that once a minimum rate of gas evolution (from volatiles or moisture) is achieved a bubble forms which is large enough to lift a fuel particle to the surface. For particles meeting this criterion, the rise-time appears to be independent of the size of the fuel particle.
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Soreanu, Gabriela, Igor Cretescu, Doina Lutic, Maria Harja i Stelian Sergiu Maier. "STUDY OF MICROALGAE INFLUENCE ON CARBON CAPTURE FROM GASEOUS STREAMS WITHIN THE BIOTRICKLING FILTRATION PROCESS". W 22nd SGEM International Multidisciplinary Scientific GeoConference 2022. STEF92 Technology, 2022. http://dx.doi.org/10.5593/sgem2022/4.1/s19.50.
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In this work, a brief assessment of using microalgae (Arthrospira platensis PCC 8005) for lowering carbon emissions during biotrickling filtration of volatile organic compounds (VOCs) from air is performed. In this regard, the removal efficiency of acetic acid vapors (used as model VOC in this study) and carbon dioxide production from this process are evaluated in the presence of: (1) classical microorganisms (e.g. from compost), (2) mixture of compost microorganisms and microalgae, (3) microalgae. A blank trial (microorganisms-free) was considered as reference. The obtained results indicate the contribution of both microorganism�s type (alone or in mixture) to the VOC removal. Remarkably, their mixture exhibited the lowest carbon emission and thus the highest environmental performance due not only VOC biodegradation, but also simultaneously carbon dioxide uptake by microalgae.
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Hickmott, Curtis, Alireza Forghani, Victoria Hutten, Evan Lorbiecki, Frank Palmieri, Brian Grimsley, Brian Coxon, Goran Fernlund i Anoush Poursartip. "A Numerical and Experimental Approach for Modeling Porosity Due to Entrapped Air and Volatiles Off-gassing During Manufacturing of Composite Structures". W SAMPE 2019 - Charlotte, NC. SAMPE, 2019. http://dx.doi.org/10.33599/nasampe/s.19.1627.
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Tandy, Jon, Vassilia Spathis i Luke Alesbrook. "Cryogenic Capture of Hypervelocity Impact Ejecta". W 2022 16th Hypervelocity Impact Symposium. American Society of Mechanical Engineers, 2022. http://dx.doi.org/10.1115/hvis2022-51.
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Abstract The capture of impact ejecta is an important tool for the evaluation of chemical modification caused by hypervelocity impact events. Traditional systems typically employ foils, foams or aerogel to capture fast moving ejecta for elemental analyses. These devices are less appropriate for the examination of more volatile components within impact ejecta and may even cause additional chemical reactions on their surface leading to uncertainties in the subsequent analyses. This is particularly disadvantageous for capture systems onboard spacecraft searching for biologically relevant molecules like amino acids. The preliminary design and testing of a cooled capture plate system utilizing a cryogenic cold finger for incorporation with the University of Kent’s two-stage light gas gun is outlined. Experiments using solid nylon sabots at a range of impact speeds were carried out with the majority of targets composed of a glycine-water ice mixture. A minimum capture plate temperature of -71 °C was achieved with an impact chamber pressure of 0.2 mbar but was observed to be closer to -30 oC during vacuum chamber evacuation using frozen targets due to sublimation of the ice’s surface. Shots at impact speeds greater than 6.3 km s-1 showed effective capture of small concentrations of glycine after derivatization and subsequent GC-MS analysis. The additional detection of glycolic acid within the captured material also suggests the potential for significant chemical modification within impact ejecta, which has important implications for the sampling of solar system plumes and surface material transferred across planetary bodies by hypervelocity impacts.
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Wang, Te-Chuan. "Comparison of Severe Accident Results by Using MAAP5 and MAAP4 Codes". W 18th International Conference on Nuclear Engineering. ASMEDC, 2010. http://dx.doi.org/10.1115/icone18-29017.
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MAAP5 (Modular Accident Analysis Program Rev. 5.0.0), developed by Fauske & Associates, Inc.’s (FAI) based on the MAAP4 code, is a severe accident analysis code. It is a computer program capable of simulating the response and mitigation actions of light water reactor nuclear power plants (NPPs), including advanced boiling water reactor (ABWR) during severe accident. A specific loss of all core cooling accident sequence, LCLP-PF-R-N, based on Final Safety Analysis Report (FSAR) of Lungmen (ABWR) NPP, was selected as a based case and simulated by the MAAP5 and MAAP4 codes. The MAAP5 and MAAP4 parameter files for Lungmen NPP were established based on Lungmen NPP design data and the MAAP5 and MAAP4 users’ guides. The main severe accident phenomena and the fission product release fractions associated with the LCLP-PF-R-N sequence were simulated. The purpose of this paper is to compare the analysis results of LCLP-PF-R-N sequence calculated by MAAP5 and MAAP4 codes. The two codes give similar results for important phenomena during the accidents, including core uncovery, core support plate failure, debris relocation to the lower plenum, vessel failure, passive flooder opens, containment overpressure protection system (COPS) activation, noble gases and volatile species (like CsI) release to environment, except for the amount of hydrogen production in core. MAAP5 predicts a greater amount of hydrogen production in core than that of MAAP4. This is because MAAP4 predicts earlier reactor pressure vessel (RPV) depressurization than that of MAAP5. That results in earlier steam exhaustion and oxidation reaction termination in core than those of MAAP5. This paper successfully demonstrates the severe accident of Lungmen NPP, and analysis results can provide useful information for the MAAP5 and MAAP4 users.
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Mohanty, Rituparna, Yogin Patel, Bryan Llumiquinga i Jonathan P. Singer. "Dynamic Mechanical Properties of Carbon Fiber Reinforced With Macropore-Infused Nanoparticle Emulsion Thermoset (MINETs)". W ASME 2024 19th International Manufacturing Science and Engineering Conference. American Society of Mechanical Engineers, 2024. http://dx.doi.org/10.1115/msec2024-125364.
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Abstract Macropore-infused nanocomposite emulsion thermosets (MINETs) represent an innovative category of nanocomposite materials synthesized using common industrial constituents such as epoxy resin, nanoparticles, a liquid porogen, and surfactant. They are prepared by creating a microphase separation of two immiscible phases (here being the polymeric resin and non-volatile oil) stabilized by a surfactant and jammed with a nanoparticle or particle blend by employing high shear mixing. Following ambient temperature curing and optional oil phase extraction through rinsing results in MINETs having open porosity at tunable length scales that can be infiltrated with selected working fluids to achieve the desired function. Optimizing the composition of MINETs facilitates the introduction of multifunctionality into the composites. This tailoring for multifunctionality involves incorporating various functional nanoparticles selected based on their application requirements. Notably, the size of the resulting pores is influenced by the choice of nanoparticles. Altogether, the function of MINET can be optimized depending on the choice and composition of the nanoparticle(s), the choice of the filler fluid, the choice of the polymeric resin, and the choice of the surfactant. The primary objective of this investigation is to affirm the viability of MINETs as a resin matrix alternative in carbon fiber composites while maintaining the mechanical resilience characteristic of traditional carbon fiber composites (CFCs). The study focuses on the incorporation of MINETs into carbon fiber composites (CFCs) and assessing the dynamic mechanical properties of the resultant structures, together with the associated challenges encountered during this process. Optimizing the MINET composition enables multifunctionality but requires an understanding of each constituent’s interaction with carbon fibers. For instance, a notable setback surfaced when attempting to integrate silica-based MINETs into the carbon fiber matrix. This endeavor yielded composites exhibiting poor mechanical properties and delamination. To mitigate these issues, carbonaceous nanoparticles were introduced into the MINET composition. The shift from silica to carbonaceous nanoparticles improved the mechanical properties of the MINET carbon fiber composite, thus highlighting the importance of the particle carbon fiber compatibility. Employing graphene as the nanoparticle of choice yielded MINETs with expected higher electrical and thermal conductivity but compromised the mechanical properties of the resulting carbon fiber composites. Subsequently, the replacement of graphene with graphite was explored, which contributed to the enhancement of mechanical properties. Nevertheless, this substitution came with repercussions, as it affected the porosity and conductivity of the MINET carbon fiber composites. The blending of graphite and graphene bore intermediate results allowing for co-optimization of the mechanical and electrical properties. However, these findings require further optimization and investigation to be termed as quantifiable components for toughening mechanisms. Ultimately, this research opens the door to a novel platform capable of integrating multifunctionality into forthcoming aerospace structures.